Can end for easy opening beverage cans



Sept. 13, 1966 J. 5. BOZEK 3,272,381

CAN END FOR EASY OPENING BEVERAGE CANS Filed March 25, 1964 E19 7 F168 F163 22 20 J J @i 14 \ld 44 INVENTOR JOHN S. BozEK ATTORNEYS United States Patent 3 272 381 CAN END FOR EASY bPENrNG BEVERAGE CANS John S. Bozek, Chicago, Ill., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Mar. 25, 1964, Ser. No. 354,663 Claims. (Cl. 220-54) This invention relates in general to new and useful improvements in cans of the easy opening type, and more particularly to a can end of the easy opening type particularly adapted for use in conjunction with a product which may be subjected to gaseous pressure at the time of the opening of an associated can.

This invention particularly relates to a can end of the easy opening type which is particularly adapted for use in the packaging and dispensing of beverages which are packaged under a gaseous pressure, although the invention may be applied equally as well to can ends which are particularly adapted for the dispensing of products other than beverages but wherein the products may be subjected to gaseous pressure at the time the associated cans are opened.

The packaging of beer and carbonated beverages has always presented problems to the can industry in that the pressures involved require stronger can construction and the possibility of blow-out is always present. The problem of blow-out due to the gaseous pressure within the can is also existent with respect to easy opening can ends. The usual easy opening can end has a removable portion which is defined by a weakening line and to which there is normally attached at one end a pull tab. In the opening of a can employing such a can end, a lifting force is applied to the pull tab with the result that the end panel of the can end is ruptured at the starting end of the removable portion. After this initial rupture of the end panel occurs, the pull tab is gripped between ones fingers and an upwardly and outwardly directed pull is exerted thereon along the general line of the removable portion of the can end. In this manner the removable portion of the can end is readily removed from the can end without any annoyance to the person opening the can end. However, it has been found with existing can end constructions of the easy opening type utilized in conjunction with beer and carbonated beverages, when there is an un due build up of pressure within the associated can, at the time the initial rupture of the can end takes place, the gaseous pressure within the can is reactive against the removable portion of the can end to the extent that the can end is immediately ruptured along the weakening line defining the removable portion and the removable portion is blown from the can end. While such a mishap is not necessarily dangerous, although it could be, it will be readily apparent that it is quite shocking to the person with whom it occurs and the net result is obviously undesirable.

The obvious solution to the problem, at first thought, would be merely to make the weakening line of a lesser weakness so that a greater force is required to rupture the end panel of the can end along the weakening line. While this would prevent the undesirable blow-out of the removable portion of the can end, it would also increase the resistance of the end panel to the removal of the removable portion to the extent that it would be undesirable.

In view of the foregoing, it is the primary object of this invention to provide a can end which is particularly adapted for use in the packaging of a product which may be subject to gaseous pressure at the time the associated can is opened, the removable portion of the can end be ing defined by a weakening line which has parts of major resistance to rupture adjacent to, but spaced from, the starting portion of the weakening line, whereby any tend- "ice ency for the continued uncontrolled rupture of the can end along the weakening line after the initial rupture of the can end due to the gaseous pressure within the associated can will be resisted by these parts of the Weakening line, and at the same time, the parts of maximum resistance to rupture will be relatively short and so spaced with respect to the starting portion of the weakening line wherein during the normal opening of the can, there will remain in advance of the part of maximum resistance weakening line portions along which the can end may be readily torn so that a momentum or inertia towards tearing may be built up before the parts of maximum resistance are reached.

Another object of this invention is to provide a Weakening line arrangement for removable portions of easy opening can ends wherein the uncontrolled rupturing of the can end due to gaseous pressure blow-off may be readily arrested and at the same time the resistance of the can end to rupture along the weakening line is not materially increased to the point where it is not practical.

Another object of this invention is to provide a weakening line in accordance with the foregoing wherein the weakening line is in the form of a score line, and the resistance to rupture due to internal gaseous pressure blowoff is controlled by a change in score line depth, a change in score line design, a change in score line contour, etc.

A further object of this invention is to make provisions in any easy opening can end of the type particularly adapted for use in the packaging of beverages under gaseous pressure to arrest the uncontrolled rupture of the can end along the weakening line formed therein due to internal gaseous pressure blow-off, arresting of the rupture due to blow-off being controlled simply by decreasing the depth of the score adjacent to, but spaced from, the starting portion of the score line and in transverse alignment whereby the effect of pressure upon the starting end of the removable portion of the can end will be to initially rupture the can end followed by a hinging or bending up of the released portion, and the reduce-d depth scored portions being relatively short and so spaced from the portion of the score line which is initially ruptured, whereby under normal conditions a sufficient rupturing momentum may be built up prior to the reaching of these parts of the score line to facilitate the ready manual tearing or rupturing of the can end along the score line portions of minimum depth.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a top perspective view of a beverage can having formed as part thereof an easy opening can end incorporating the spirit of this invention.

FIGURE 2 is an enlarged fragmentary perspective view of the central portion of the can end of FIGURE 1 and shows the can end as it would appear after the initial rupturing of the can end due to an upwardly directed force on the associated pull tab followed by a further rupturing of the can end due to blow-off and wherein the further rupturing has been arrested.

FIGURE 3 is an enlarged fragmentary perspective view similar to FIGURE 2 and shows the can end as it appears after the normal initial rupturing thereof utilizing the pull tab.

FIGURE 4 is an enlarged fragmentary plan view showing schematically the score line arrangement of the can end.

FIGURE 5 is an enlarged fragmentary plan view along a portion of the score line which includes a part of maximum resistance to rupture.

FIGURE 6 is an enlarged fragmentary longitudinal sectional view taken along the line 66 of FIGURE and shows more clearly the variations in score line depths.

FIGURE -7 is an enlarged fragmentary transverse vertical sectional view taken along the line 7-7 of FIGURE 6 and shows the specific cross section of the score line throughout the major portion of the length thereof.

FIGURE 8 is an enlarged fragmentary transverse vertical sectional view taken along the line 88 of FIGURE 6 and shows the cross section of the score line through the blow-out arresting part thereof.

FIGURE 9 is an enlarged fragmentary vertical sectional view taken along the line 9-'9 of FIGURE 4 and shows the cross section of the score line of the starting part thereof.

Referring now to the drawing in detail, it will be seen that there is illustrated in FIGURE 1 a can which is generally referred to by the numeral 10 and which is particularly adapted for the dispensing of liquids, particularly beverages. The-can 10 includes a conventional can body 11 to which there is secured by means of a double seam 12 a can end 13 which is formed in accordance with this invention. The illustrated can end 13 includes an end panel 14 in which a continuous score line 15 is formed to define a removable portion 16. When the removable portion 16 is removed from the can end 13, a suitable combined pour and vent opening is formed.

Referring now to FIGURE 4 in particular, it will be seen that the removable portion 16 includes a starting end "17, an intermediate tear strip portion 18 and an enlarged terminal part 19. It will also be seen that the score line 15 includes a starting portion which extends generally around the starting part 17 of the removable portion 16. The starting portion 20 of the score line flows into a normal score line portion 21 which extends along the tear strip portion 18 and the enlarged terminal part 19 of the removable portion 16. However, the normal score line portion 21 is interrupted intermediate the ends of the tear strip portion 18 by two transversely aligned score line portions 22 which are for the purpose of arresting any uncontrolled rupture of the score line 15 due to a blow-out of the contents of the can 10 after the initial rupture of the end panel along the starting portion 20 of the score line 15. The specific details of the score line '15 will be described hereinafter.

In order to facilitate the tearing of the removable portion 16 from the can end 13, the removable portion 16 is provided at the starting end 17 thereof with an upstanding integral rivet 23. The rivet 23 is utilized for the purpose of securing a pull tab 24 to the removable portion 16. After the pull tab 24 has been passed over the rivet 23, the rivet 23 is upset to define an enlarged head 25 which securely clamps the pull tab 24 in place.

Referring now to FIGURES 4 through 9, it will be seen that although the upper portion of the score line 15 is of a constant width throughout the length of the score line, the score line varies in depth. The starting portion 20 of the score line is of a maximum depth, as is illustrated in FIGURE 9. On the other hand, as is shown in FIGURE 7, the normal score line portion 21 is of an average depth. On the other hand, the score line part 22 is of a very shallow depth. The specific details of the score line 15 along the tear strip part 18 of the removable portion 16 are clearly shown in FIGURES 5 and 6. This clearly shows the score line 15 to be of a constant width. However, since the blow-out arresting part 22 of the score line 15 is much shallower than the normal score line portion 21, it is wider at the base. Accordingly, since the die for forming all of the score line 15 is of the same taper, it will be seen that the base of the score line part 22 is much wider than the base of the score line portion 21.

In order to identify the extent of the score line parts 22, in FIGURES 2, 3 and 4 there will be found lines A-A and B,B which extend transversely of the removable portion 16 at the opposite ends of the score line parts 22.

Referring now to FIGURE 3 in particular, it will be seen that when the can 10 is opened in the normal manner by exerting an upwardly directed pressure on the end of the pull tab 24 remote from the rivet 23, the end panel 14- will be ruptured along the starting portion 20 of the score line 15. This initial rupturing of the end panel 14 will be for a relatively short distance and will normally terminate short of the score line part 22. On the other hand, if there is excessive pressure within the can 10 and there is a tendency for the pressurized gas and possibly portions of the contents of the can 10 to blow out through the opening formed upon the initial rupturing of the end panel 14, it will be seen that the starting end 17 of the removable portion 16 will be blown upwardly and there will be momentary uncontrolled rupturing of the end panel 14 along the score line 15. When the score line :15 is of a constant depth continuing from the ends of the starting portion 20, such as that shown in FIGURE 7, in many instances the blow-out pressure exerted on the removable portion 16 will be sufficient to effect a continued uncontrolled rupturing of the end panel along the score line 15 so that the entire removable portion 16 is undesirably blown out from the end panel 14.

In accordance with this invention, as is shown in FIG- URE 2, if there should be sufiicient blow-out pressure to effect the uncontrolled rupturing of the end panel along the score line 15 after the initial rupturing of the end panel along the score 'line starting portion 20, as is shown in FIGURE 3, then the entire starting end 17 of the removable portion 16 will be torn loose from the end panel 14. Furthermore, there will be a tearing of that part of the tear strip portion 18 adjacent the starting end 17 from the end panel 14. However, since the score line parts 22 are of minimum depth, as is shown in FIGURE 8, the uncontrolled rupturing of the end panel 14 along the score line 15 will momentarily halt and there will be an upward hinging of that part of the removable portion 16 which has torn free of the end panel 14, as is shown generally in FIGURE 2. Thus, the minimum depth parts 22 of the score line 15 function as means for preventing the uncontrolled rupturing of the end panel 14 along the score line 15 due to blow off.

It is to be understood that the tearing force by blowoif pressure is not as great as that which can be exerted by one conveniently pulling on the pull tab 24. Accordingly, even if initial rupture due to blow-off does occur and the end panel 14 is ruptured to the extent shown in FIGURE 2, the controlled continued rupture of the end panel 14 along the score line 15 can be readily accomplished. Furthermore, since the initial rupture of the end panel 14 is only along the starting portion 20 of the score line under normal opening conditions, as is shown in FIGURE 3, when the pull tab 24 is gripped for tearing out the removable portion 16 in the normal manner, the initial tearing will be along the normal depth score line portion 21 so that a tearing inertia may be attained before the score line parts 22 of maximum resistance are reached. Because of this inertia of tearing, the removable portion 16 may be readily torn from the end panel 14 notwithstanding the function of the tear line parts 22 to prevent uncontrolled blow out of the removable portion 16.

Although the specific score line arrangement of this invention has been illustrated in conjunction with only a beverage can, it is to be understood that the principles of the invention may be incorporated in other types of easy opening cans. Furthermore, while the score line parts 22 of maximum resistance have been illustrated as being only shallow in the normal score line portions, it is to be understood that in accordance with this invention, the resistance to tearing along the score line may be controlled in other ways including a change in score line design, a change in score line contour, etc.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made within the scope of the invention, as defined by the appended claims.

Iclaim:

1. A can end of the easy opening type particularly adapted for the dispensing of a product which may be under gaseous pressure, said can end including an end panel having a portion defined by a weakening line and being removable to define a dispensing opening, said removable portion having a starting end defined by a starting weakening line portion along which said end panel is initially ruptured in the removal of said removable portion, said weakening line including other portions extending from said starting weakening line portion and including parts of maximum resistance whereby when said end panel is initially ruptured and uncontrolled continued rupture of said end panel along said weakening line due to gaseous pressure on said removable portion occurs said parts of maximum resistance will resist and stop the uncontrolled rupture.

2. The can end of claim 1 wherein said parts of maximum resistance are spaced from said weakening line starting portion whereby after an initial rupture occurs portions of said weakening line remain in advance of said parts of maximum resistance and tearing inertia may be built up before said parts of maximum resistance are reached;

3. A can end of the easy opening type particularly adapted for the dispensing of a product which may be under gaseous pressure, said can end including an end panel having a portion defined by a weakening line and being removable to define a dispensing opening, said removable portion having a starting end defined by a starting weakening line portion along which said end panel is initially ruptured in the removal of said removable portion, said removable portion including a tear strip portion defined by intermediate weakening line portions, and said intermediate weakening line portions each including a weakening line part of maximum resistance whereby when said end panel is initially ruptured and uncontrolled continued rupture of said end panel along said weakening line due to gaseous pressure on said removable portion occurs said parts of maximum resistance will resist and stop the uncontrolled rupture.

4. The can end of claim 3 wherein said parts of maximum resistance are spaced from said weakening line starting portion whereby after an initial rupture occurs portions of said weakening line remain in advance of said parts of maximum resistance and tearing inertia may be built up before parts of maximum resistance are reached.

5. A can end of the easy opening type particularly adapted for the dispensing of liquids packaged under gaseous pressure, said can end including an end panel of which a portion is defined by a weakening line and being readily removable to define a pour opening, said removable portion including a starting end to which a pull tab may be secured, an enlarged terminal part and an intermediate strip part, the portions of said weakening line defining said strip part including parts of maximum resistance whereby when said end panel is initially ruptured and uncontrolled continued rupture of said end panel along said weakening line due to gaseous pressure on said removable portion occurs, said parts of maximum resistance will resist and stop the uncontrolled rupture.

6. The can end of claim 5 wherein said weakening line is in the form of a score line and said parts of maximum resistance are achieved by means of controlled scoring.

'7. The can end of claim 5 wherein said weakening line is in the form of a score line and said parts of maximum resistance are of minimum score depth.

8. A can end of the easy opening type particularly adapted for the dispensing of a product which may be under gaseous pressure, said can end including an end panel having a portion defined by a weakening line and being removable to define a dispensing opening, said removable portion having a starting end defined by a starting weakening line portion along which said end panel is initially ruptured in the removal of said removable portion and a terminal portion, and said end panel having means intermediate said starting weakening line portion and said terminal portion for resisting the normal tearing of said can end along said weakening line and preventing the uncontrolled continued rupture of said end panel along said weakening line due to gaseous pressure on said removable portion.

9. The can end of claim 8 wherein said means includes portions of said end panel along said weakening line of maximum resistance to tearing.

10. The can end of claim 8 wherein said means includes portions of said end panel along said weakening line of maximum thickness as compared to the thickness of said end panel along adjacent portions of said weakening line.

References Cited by the Examiner UNITED STATES PATENTS D. 195,604 7/1963 Fraze 22054 3,005,573 10/1961 Dawson et al. 220-89 3,034,680 5/1962 Steinberg 220-27 THERON E. CONDON, Primary Examiner.

G. T. HALL, Assistant Examiner. 

1. A CAN END OF THE EASY OPENING TYPE PARTICULARLY ADAPTED FOR THE DISPENSING OF A PRODUCT WHICH MAY BE UNDER GASEOUS PRESSURE, SAID CAN END INCLUDING AN END PANEL HAVING A PORTION DEFINED BY A WEAKENING LINE AND BEING REMOVABLE TO DEFINE A DISPENSING OPENING, SAID REMOVABLE PORTION HAVING A STARTING END DEFINED BY A STARTING WEAKENING LINE PORTION ALONG WHICH SAID END PANEL IS INITIALLY RUPTURED IN THE REMOVAL OF SAID REMOVABLE PORTION, SAID WEAKENING LINE INCLUDING OTHER PORTIONS EXTENDING FROM SAID STARTING WEAKENING LINE PORTION AND INCLUDING PARTS OF MAXIMUM RESISTANCE WHEREBY WHEN SAID END PANEL IS INITIALLY RUPTURED AND UNCONTROLLED CONTINUED RUPTURE OF SAID END PANEL ALONG SAID WEAKENING LINE DUE TO GASEOUS PRESSURE ON SAID REMOVABLE PORTION OCCURS SAID PARTS OF MAXIMUM RESISTANCE WILL RESIST AND STOP THE UNCONTROLLED RUPTURE. 